The present invention relates to a conveyor boom which is mounted to the superstructure of a large-scale conveyor so as to be raised and lowered in a vertical plane, such as a belt boom for a stacker, a discharge belt boom for a bucket wheel excavator or the like.
Bucket wheel excavators are known which are equipped with a discharge belt which is pivotally mounted in the superstructure of the bucket wheel excavator so as to be pivotal as well as raisable and lowerable for adjustment of its height. It is also known to suspend the rear end of the discharge belt boom from the superstructure so that it can be raised and lowered in an articulated manner about a horizontal axis in order to permit the discharge belt to be guided at different slopes. Such a device is disclosed in DE-GM 7229102 which is the priority application of U.S. Pat. No. 3,828,913. In such a type of mounting of the discharge belt boom, the conveyor belt is stressed differently at the point of articulation depending on the setting of the discharge belt boom. If the downward angle is excessive, the upper reach of the conveyor belt is stretched and the lower reach is compressed. On the other hand, if the discharge belt boom is pivoted upwardly, the reverse stretching and compression stresses occur at the conveyor belt.
The periodical "Hebezeuge und Foeller rdermittel" [Lifting and Conveying Equipment], Berlin 27, 1987, page 104 et seq. describes direct drop stackers in which a discharge belt is also mounted at a superstructure so as to be raised and lowered. The stresses on the conveyor belt at the point where the discharge belt boom is attached vary depending on whether the discharge belt boom is pivoted upwardly or downwardly. The different stresses on the conveyor belt at the point of its sharp bend may lead to operational malfunctions. Also, wear of the discharge belt is increased.